Thread: finding the rate of change of height of cone.

maths prob.bmp

Hi guys, i am having problem to solve the above question, i seem not able to get the correct answer each time i try out.

Hope someone could help me out. Thanks.

Think of the volume of water in the conical container as being composed of circular disks of thickness . We may then state:



We know the ratio of the radius of the water's surface to the height of the water level will be the same as that of the container:

hence:



Now, solve for and use the given values of to compute the requested value.